The United States says it will work closely with China on ways to regulate trade in genetically modified agricultural products. Washington is concerned that China's tough new rules on bio-engineered food will hurt U.S. farm exports.

The U.S. Secretary of Agriculture, Ann Veneman, says Chinese officials have assured her that China's new regulations on the import of genetically modified food will not impede trade with the United States.

But Ms. Veneman told reporters in Beijing Tuesday that some American exporters are worried about the restrictions, which require them to face tougher inspection standards. "We want to make sure that uncertainty in the market doesn't create an unintended trade effect, so it's important that we clearly have the same understanding in both countries about how the regulations will be implemented," she said.

Speaking after several days of meetings with Chinese officials, Ms. Veneman said U.S. soybean exports to China have fallen recently. She said many American companies are confused about the Chinese rules on products containing genetically modified organisms (GMO). Last year, the United States exported $1 billion worth of soybeans to China, most of which were bio-engineered.

Ms. Veneman said the United States and China have agreed to set up a working group to make sure bio-technology regulations are based on science, and are not used as "disguised trade barriers."

Chinese and American agricultural trade officials are expected to meet again within the next several days to discuss the issue.

Chinese officials have defended the new rules, announced last year and due to take effect permanently this December. Officials say they merely want to ensure that GMO products are not harmful to consumers.

At a separate news conference in Beijing Tuesday, Gao Yan, spokeswoman for China's Ministry of Foreign Trade, said China is very concerned about ensuring the quality and safety of its food and other products.

On Monday, the official China Daily newspaper said the dispute over GMO products could turn out to be a time bomb in Sino-American relations if the two countries fail to resolve their differences.